(Press-News.org) The leading theory for why the blood of younger mice rejuvenates the muscles of older mice is now in contest. The vampiric exchange of young blood and old blood has long been reported to have anti-aging effects, but it was in 2013 when Harvard University researchers first linked GDF-11, a molecule that circulates in the blood, to this effect.
Now, an analysis that set out to see how GDF-11 works in the muscles published May 19 in Cell Metabolism found just the opposite. The investigators showed first that GDF-11 was not specifically measured; the methods that were previously used were not specific for GDF-11, but also measured another molecule it closely resembles, called myostatin, which is well known to inhibit muscle growth.
The new study, led by David Glass at the Novartis Institutes for BioMedical Research, in collaboration with Massachusetts General Hospital and the University of California, San Francisco, used tests to more accurately measure GDF-11 (short for Growth Differentiation Factor 11) in the blood of animals and humans and found that it showed hints of increasing with age, and clearly did not decrease with age. They also show that regularly injecting mice with pure GDF-11 causes muscle repair to worsen, resembling effects seen in older age.
"This is a carefully conducted study that is certain to generate a vigorous discussion about what role GDF-11 plays, if any, in aging muscle," says Se-Jin Lee, an expert on growth/differentiation factors and molecular biologist at Johns Hopkins University who did not participate in the research.
"I think that these new results definitely raise questions as to whether GDF-11 was really being exclusively detected in the prior paper," Lee adds. "Clearly, these discrepancies will need to be resolved with additional studies, especially given the enormous effort being undertaken in the pharmaceutical community to target the myostatin pathway to treat muscle loss."
Giving GDF-11 at doses previously used in aged animals did not improve regeneration, as previously claimed. When younger animals were treated with GDF-11, regeneration was worsened. The authors developed a test that could detect GDF-11 levels specifically and suggest that, for humans, testing for high levels of GDF-11 could potentially make them eligible for medicines that block GDF-11 activity.
"Clearly, like the mythical fountain of youth, GDF11 is not the long sought rejuvenation factor," write Caroline Brun and Michael A. Rudnicki of the Ottawa Hospital Research Institute in a preview to the Cell Metabolism paper. They say, given these new findings, "the suggested 'rejuvenating' activity of GDF11 in the heart and brain should also be re-examined - since the underlying premise of those other two manuscripts, that GDF11 decreases with age, is contradicted by [the new] manuscript."
INFORMATION:
This work was funded by the Novartis Institutes for BioMedical Research.
Dr. Se-Jin Lee, quoted in the press release, is under a licensing agreement with Pfizer and entitled to a share of future sales royalty received by Johns Hopkins University for technology related to myostatin, as well as a consultant to Ascelegen.
Cell Metabolism, Egerman et al.: "GDF11 increases with age and inhibits skeletal muscle regeneration" DOI: http://dx.doi.org/10.1016/j.cmet.2015.05.010
Cell Metabolism, published by Cell Press, is a monthly journal that publishes reports of novel results in metabolic biology, from molecular and cellular biology to translational studies. The journal aims to highlight work addressing the molecular mechanisms underlying physiology and homeostasis in health and disease. For more information, please visit http://www.cell.com/cell-metabolism. To receive media alerts for Cell Metabolism or other Cell Press journals, contact press@cell.com.
Chicago -- May 14, 2015 -- Infants undergoing some types of surgery could have better recovery if they receive regional anesthesia rather than general anesthesia, according to two studies published in the Online First edition of Anesthesiology, the official medical journal of the American Society of Anesthesiologists® (ASA®). Researchers explored the differences between the two types of anesthesia by measuring the presence of apnea, a breathing complication, following hernia surgery.
Experts have long examined the effects of anesthesia on infants and toddlers, ...
With the help of a computer program called "Rosetta," researchers at Vanderbilt University have "redesigned" an antibody that has increased potency and can neutralize more strains of the AIDS-causing human immunodeficiency virus (HIV) than can any known natural antibody.
Their findings, published online today in The Journal of Clinical Investigation, suggest that computer-redesigned antibodies may speed the search for an effective therapy or vaccine for a virus that so far has eluded all attempts to eradicate it.
"There's a consensus (in the HIV field) that the vaccine ...
WASHINGTON --The best remedy for severe salicylate poisoning is hemodialysis, according to a comprehensive systematic review of the medical literature published on Friday in Annals of Emergency Medicine ("Extracorporeal Treatment for Salicylate Poisoning: Systematic Review and Recommendations from the EXTIRP Workgroup"). Salicylate is an active ingredient in aspirin as well as hundreds of over-the-counter medications, and contributes to approximately 20,000 accidental or intentional poisonings and nearly 30 deaths reported to US Poison Control Centers every year.
"Our ...
Using nature for inspiration, a team of Northwestern University scientists is the first to develop an entirely artificial molecular pump, in which molecules pump other molecules. This tiny machine is no small feat. The pump one day might be used to power other molecular machines, such as artificial muscles.
The new machine mimics the pumping mechanism of life-sustaining proteins that move small molecules around living cells to metabolize and store energy from food. For its food, the artificial pump draws power from chemical reactions, driving molecules step-by-step from ...
JACKSONVILLE, Fla. -- Patients with liver cancer can be cured with a liver transplant. But because of the shortage of donated organs, these patients often die waiting for a liver. That's because most transplant centers predominantly use livers from donors who die from brain death.
But in the largest study of its kind, transplant physicians at Mayo Clinic in Florida have found that liver cancer patients have the same beneficial outcomes using organs donated by patients who died of cardiac death. The study was recently published online in the American Journal of Transplantation.
MULTIMEDIA ...
(New York, May 19, 2015) -- The largest urban health systems, which serve as safety nets for large patient populations with lower socioeconomic status and greater likelihood to speak English as a second language, do worse on government patient satisfaction scores than smaller, non-urban hospitals likely to serve white customers with higher education levels, according to a new study by Mount Sinai researchers published this month in the Journal of Hospital Medicine.
Patient satisfaction scores, in part due to the Affordable Care Act of 2010, are a key part of the formula ...
ANN ARBOR--A class of FDA-approved cancer drugs may be able to prevent problems with brain cell development associated with disorders including Down syndrome and Fragile X syndrome, researchers at the University of Michigan Life Sciences Institute have found.
The researchers' proof-of-concept study using fruit fly models of brain dysfunction was published today in the journal eLife. They show that giving the leukemia drugs nilotinib or bafetinib to fly larvae with the equivalent of Fragile X prevented the wild overgrowth of neuron endings associated with the disorder. ...
For the patient, surgery involves extreme physical stress, and in older patients especially this can lead to disorders of consciousness or cognition. The acute confusional state known as delirium, however, can often be prevented by specialist nursing care after the operation, as Torsten Kratz and co-authors show in an original article in the current issue of Deutsches Ärzteblatt International (Dtsch Arztebl Int 2015; 112: 289-96). In their study delirium liaison nurses were employed to help care for surgical patients aged 70 years and over. In every patient, the risk ...
Preschoolers already recognize what it feels like to be left out when goodies are being shared. In a new study, Researchers at Ludwig-Maximilians-Universitaet (LMU) in Munich show that 3-year-olds can anticipate negative feelings in others, and adjust their own behavior in response.
Why are we willing to share with others what we could just as well keep for ourselves? Willingness to allot a portion of a coveted resource to someone else is a behavioral pattern that can throw light on the origins and development of prosocial modes of response during childhood. In a new ...
TAMPA, Fla. -- Cells within a tumor are not the same; they may have different genetic mutations and different characteristics during growth and throughout treatment. These differences make treating tumors extremely difficult and often lead to tumor recurrence dominated by more aggressive tumor cells. Moffitt Cancer Center researchers are using mathematical modeling to characterize these differences within a tumor and hope that the results of their latest study will lead to better therapeutic treatments.
"Many tumors exhibit different metabolic behaviors compared to normal ...
